General Motors Co. is closing its plant in Pontiac, Mich., that assembles the full-size Chevrolet Silverado/GMC Sierra pickup trucks.

A third shift will be added to the truck plant in Fort Wayne, Ind., to fill in production.

The Pontiac plan was one of 14 GM named earlier that would be closed or production significantly changed as part of its long term program to trim its size. The plant employs about 1,000 workers.

High fuel prices last year and the lengthening recession have cause sales of full-size pickup trucks to fall.

By Light & Medium Truck